Tablet forming machine



Jan. 9, 1962 H. c. EDGAR ETAL TABLET FORMING MACHINE 3 Sheets-Sheet 1Filed March 4, 1959 FIG MMXM

ATTORNEYS Jan. 9, 1962 H. c. EDGAR ETAL TABLET FORMING MACHINE 3Sheets-Sheet 2 Filed March 4, 1959 FIG. 2

' INVENTORS' HUGH C. EDGAR & LEO P. GAJDA ATTORNEYS llllllllll '40 30 4o42 BY Jan. 9, 1962 H. c. EDGAR ETAL TABLET FORMING MACHINE 5Sheets-Sheet 3 Filed March 4, 1959 28 INVENTORS Hue C. Ens/m & Leo RGAJDA zamw, km KM Y M ATTORNEYS United States Patent 3,016,027 TABLETFORlViING MACHINE Hugh C. Edgar and Leo P. Gajda, Detroit, Mich.,assign- Ol's to Arthur Colton (30., Detroit, Mich., a corporation ofMichigan Filed Mar. 4, 1959, Ser. No. 797,139 6 Claims. (Cl. 10717) Thisinvention relates to a tablet forming machine and particularly to thattype of machine where tablets or tablet coatings are created frompowdered material by the application of pressure.

Reference is made to co-pending application of Adolf Gustav Gross,Serial No. 791,660, filed February 6, 1959, for a disclosure on thistype of machine.

It is an object of the present invention to provide an improved designof a means for feeding powdered material to the die pockets of a tabletforming machine.

It is a further object to provide a simplified drive mechanism for themovement of parts of the assembly and an improved bottom design for thesupport of the material as it moves into the dies.

Other objects and features of the invention relating to details ofconstruction and operation will be apparent in the following descriptionand claims.

Drawings accompany the disclosure and the various views thereof may bebriefly described as:

FIGURE 1, an elevation of the assembly of the device.

FIGURE 2, a sectional view on line 2-2 of FIGURE 1 showing certaindetails of the operating parts.

FIGURE 3, a sectional view on line 33 of FIG- URE 1.

FIGURE 4, a sectional view on line 4-4 of FIG- URE 2.

A capsule forming machine utilizing revolving die pockets and punches isknown in the industry and the details of a capsule coating machine arefully illustrated and described in co-pending application, Serial No.696,- 200, filed November 13, 1957, now Patent No. 2,946,298, dated July26, 1960. These devices utilize a feed hopper for the powdered materialalong with what is called a feed shoe which is an enlarged flat chamberoverlying the rotating die pockets. The present disclosure is related tothis type of machine.

In FIGURE 1 the fill hopper 20 is shown supported above the machine bysuitable bracket 22, this feed hopper having a throat portion 24 leadingdownwardly into the chamber 26 comrnonly referred to as a feed shoe. InFIGURE 4, the horizontal sectional outline of the feed shoe 26 is shownmore plainly, this being in the shape of an oval shaped chamber, thehousing having an outer flange 28 for clamping the feed shoe downagainst a kidney-shaped base plate 30. The base plate has a concavicallycurved forward edge 32 with a chamfer formation, the base plate beingmounted on a base frame 34. The curvature of the edge 32 of the baseplate corresponds to the circumference of the rotating die pocket ring40 and the edge of the base plate 30 overlies the edge of the rotatingring as shown in FIG- URES 2 and 4.

The ring 40 has traveling punches 42, FIGURE 2, sometimes referred to asbottom dies and above the rotating ring or die pocket plate are theupper die punches 44, these punches being controlled by cams such asshown at 46. Between the rotating die pocket ring 40 and the base framefor the bottom plate 30 is a strip of plastic material 50, such asTeflon, which is a relatively tough plastic with a good bearingcharacteristic and also slightly fiowable. This Teflon strip is clampedclosely between the periphery of the die ring 40 and the supportingframe 34 of the base plate. In the working-in of the parts this Teflonwill conform itself to the die ring and create a very tight fit betweenthis ring and the bottom surface of the plate 30, thus providing a veryeffective seal for any powder that may work under the edge 32 of theplate 30.

The object of the device is to fill the die pockets 60 of the die ring40 and to obtain a constant uniform charge in each of these die pockets.This is facilitated by the location in the shoe chamber 26 of two rotors62 each of which has radial spokes 64 and 66. These spokes are spacedupwardly from the bottom plate 30 and each has a number of vertical pinsequally spaced on the spokes and extending downwardly and upwardly inthe feed shoe chamber. Spokes 64 have four pins and spokes 66 have threepins, these three pins being spaced radially to fall in the area betweenthe four pins.

The rotors are each mounted on a rotating shaft 70 passing up through abearing housing 72 containing a bushing 74. On the top of the shaft ineach case is a gear preferably formed of a material such as nylon heldby a plate 82. The gears 80 are formed with spaced peripheral pockets 84adapted to engage the upper die punches or plungers 44 as they rotatearound with the die pocket ring. Thus both the rotors will rotate in thesame direction clockwise as shown in FIGURES 3 and 4. With thisarrangement the faster the machine is operated the faster will therotors move in the feeding chamber. It is an object to move the powderedmaterial into the feeding chamber in a manner that a gentle pressurewill be built up over the rotating die pocket plate so that materialwill be packed in uniformly without air pockets to insure completefilling in each case.

We claim:

1. In a tablet forming machine of the type utilizing a rotatable diering having circumferentially spaced pockets, a filling device formoving charges of compactable material into said pockets comprising achamber to overlie said die ring including an open-bottom housingextending both inwardly and outwardly over a segment of the outerperipheral portion of said die ring, a material feeding inlet located insaid housing, a bottom for said housing closing the portion of saidhousing outside of said die periphery and extending into overlyingrelation with the peripheral portion of said die ring outwardly of saidspaced pockets, said overlying portion having an edge curved similar tothe periphery of the die, and rotatable means in said chamber movingover said die ring to carry material into said die pockets.

2. In a device of the type defined in claim 1, a means underlying saidbottom and in close peripheral contact with the die ring comprising astrip of plastic material having characteristics of flowability underpressure, said means serving to seal said area against escape ofmaterial being handled.

3. In a device of the type defined in claim 1, a frame means underlyingsaid bottom to support the same having a contour simila to said diering, and a bearing strip tightly interposed between said ring and saidframe means and subjacent the bottom, said strip being formed of aplastic material having characteristics of flowability under pressure,whereby said strip conforms to the periphery of said die ring and thesurface of said bottom to seal said area against escape of materialbeing handled.

4. A device as defined in claim 1 in which bearing means are mounted insaid housing, a bearing shaft in said bearing means, said rotatablemeans comprising a star wheel on said shaft having a path sweeping oversaid bottom plate and over said die pockets of said die ring.

5. A device as defined in claim 4 in which rotatable, circumferentiallyspaced die punches are mounted to rotate with said ring, and gear meanson said bearing shaft having peripheral recesses to mesh with saidpunches rial feeding inlet located in said housing, a bottom for saidhousing closing the portion of said housing outside of said dieperiphery and including a means in close peripheral contact with saiddie ring, said means comprising a strip of plastic material havingcharacteristics of flowability under pressure, said means serving toseal said area against escape of material being handled, said.

bottom having an edge curved similar to the periphery of the die, androtatable means'in said chamber moving over said die ring to carrymaterial into said pockets.

References Cited in the file of this patent UNITED STATES PATENTS1,289,570 Stokes Dec. 31, 1918 2,043,086 Westin et a1 June 2, 1936FOREIGN PATENTS 731,600 Great Britain June 8, 1955 ma a

